13 2.3.222 Radiation Sensors - Pyranometers and actinometers are used to measure the global radiation. - Bimetallic actinographs are simple self-contained recorders. A mechanical linkage is used to record the temperature difference between a black coated bimetallic strip exposed to the sun and one or two similar bimetallic strips either painted white or shielded from solar radiation. (Suppliers: A 3) - The Moll-Gorczynki pyranometer is a thermopile instrument, having a rectangular receiving surface which is covered by two concentric hemispheric glass domes. The Volachine pyranometer is of similar construction but has a circular